1. Technical Field
The present disclosure relates to lens holders, and particularly to a hole expanding device for a lens holder.
2. Description of Related Art
Many lens modules with a focusing function include at least one guide rod and a lens holder, where the lens holder defines at least one guide hole. The guide rod is held steady by the guide holes. However, if a gap between the guide rod and the guide holes is too large, the guide rod will not be held securely. If the gap is too small, the guide rod will be too difficult to move. Methods for making the guide holes involve a hole expanding rod expanding the holes by heating. However, as the hole expanding rod enters through the guide holes, different contact times between the guide holes and the hole expanding rod result in uneven diameters of the guide holes.
Therefore, it is desirable to provide a hole expanding device that can overcome the above-mentioned problems.